diff -urN newtree/Documentation/dsdt-initrd.txt newtree.2/Documentation/dsdt-initrd.txt --- newtree/Documentation/dsdt-initrd.txt 1969-12-31 16:00:00.000000000 -0800 +++ newtree.2/Documentation/dsdt-initrd.txt 2006-08-04 10:39:02.000000000 -0700 @@ -0,0 +1,98 @@ +ACPI Custom DSDT read from initramfs + +2003 by Markuss Gaugusch < dsdt at gaugusch dot org > +Special thanks go to Thomas Renninger from SuSE, who updated the patch for +2.6.0 and later modified it to read inside initramfs +2004 - 2006 maintained by Eric Piel < eric dot piel at tremplin-utc dot net > + +This option is intended for people who would like to hack their DSDT and don't want +to recompile their kernel after every change. It can also be useful to distros +which offers pre-compiled kernels and want to allow their users to use a +modified DSDT. In the Kernel config, enable the initial RAM filesystem support +(in Device Drivers|Block Devices) and enable ACPI_CUSTOM_DSDT_INITRD at the ACPI +options (General Setup|ACPI Support|Read custom DSDT from initrd). + +A custom DSDT (Differentiated System Description Table) is useful when your +computer uses ACPI but problems occur due to broken implementation. Typically, +your computer works but there are some troubles with the hardware detection or +the power management. You can check that troubles come from errors in the DSDT by +activating the ACPI debug option and reading the logs. This table is provided +by the BIOS, therefore it might be a good idea to check for BIOS update on your +vendor website before going any further. Errors are often caused by vendors +testing their hardware only with Windows or because there is code which is +executed only on a specific OS with a specific version and Linux hasn't been +considered during the development. + +Before you run away from customising your DSDT, you should note that already +corrected tables are available for a fair amount of computers on this web-page: +http://acpi.sf.net/dsdt . If you are part of the unluckies who cannot find +their hardware in this database, you can modify your DSDT by yourself. This +process is less painful than it sounds. Download the Intel ASL +compiler/decompiler at http://www.intel.com/technology/IAPC/acpi/downloads.htm . +As root, you then have to dump your DSDT and decompile it. By using the +compiler messages as well as the kernel ACPI debug messages and the reference book +(available at the Intel website and also at http://www.acpi.info), it is quite +easy to obtain a fully working table. + +Once your new DSDT is ready you'll have to add it to an initrd so that the +kernel can read the table at the very beginning of the boot. As the file has +to be accessed very early during the boot process the initrd has to be an +initramfs. The file is contained into the initramfs under the name /DSDT.aml . +To obtain such an initrd, you might have to modify your mkinitrd script or you +can add it later to the initrd with the script appended to this document. The +command will look like: +initrd-add-dsdt initrd.img my-dsdt.aml + +In case you don't use any initrd, the possibilities you have are to either start +using one (try mkinitrd or yaird), or use the "Include Custom DSDT" configure +option to directly include your DSDT inside the kernel. + +The message "Looking for DSDT in initramfs..." will tell you if the DSDT was +found or not. If you need to update your DSDT, generate a new initrd and +perform the steps above. Don't forget that with Lilo, you'll have to re-run it. + + +======================= Here starts initrd-add-dsdt =============================== +#!/bin/bash +# Adds a DSDT file to the initrd (if it's an initramfs) +# first argument is the name of archive +# second argurment is the name of the file to add +# The file will be copied as /DSDT.aml + +# 20060126: fix "Premature end of file" with some old cpio (Roland Robic) +# 20060205: this time it should really work + +# check the arguments +if [ $# -ne 2 ]; then + program_name=$(basename $0) + echo "\ +$program_name: too few arguments +Usage: $program_name initrd-name.img DSDT-to-add.aml +Adds a DSDT file to an initrd (in initramfs format) + + initrd-name.img: filename of the initrd in initramfs format + DSDT-to-add.aml: filename of the DSDT file to add + " 1>&2 + exit 1 +fi + +# we should check it's an initramfs + +tempcpio=$(mktemp -d) +# cleanup on exit, hangup, interrupt, quit, termination +trap 'rm -rf $tempcpio' 0 1 2 3 15 + +# extract the archive +gunzip -c "$1" > "$tempcpio"/initramfs.cpio || exit 1 + +# copy the DSDT file at the root of the directory so that we can call it "/DSDT.aml" +cp -f "$2" "$tempcpio"/DSDT.aml + +# add the file +cd "$tempcpio" +(echo DSDT.aml | cpio --quiet -H newc -o -A -O "$tempcpio"/initramfs.cpio) || exit 1 +cd "$OLDPWD" + +# re-compress the archive +gzip -c "$tempcpio"/initramfs.cpio > "$1" + diff -urN newtree/drivers/acpi/Kconfig newtree.2/drivers/acpi/Kconfig --- newtree/drivers/acpi/Kconfig 2006-08-02 07:14:15.000000000 -0700 +++ newtree.2/drivers/acpi/Kconfig 2006-08-04 10:39:02.000000000 -0700 @@ -289,6 +289,23 @@ Enter the full path name to the file which includes the AmlCode declaration. +config ACPI_CUSTOM_DSDT_INITRD + bool "Read Custom DSDT from initramfs" + depends on BLK_DEV_INITRD + default y + help + The DSDT (Differentiated System Description Table) often needs to be + overridden because of broken BIOS implementations. If this feature is + activated you will be able to provide a customized DSDT by adding it + to your initramfs. For now you need to use a special mkinitrd tool. + For more details see or + . If there is no table found, it + will fallback to the custom DSDT in-kernel (if activated) or to the + DSDT from the BIOS. + + Even if you do not need a new one at the moment, you may want to use a + better implemented DSDT later. It is safe to say Y here. + config ACPI_BLACKLIST_YEAR int "Disable ACPI for systems before Jan 1st this year" if X86_32 default 0 diff -urN newtree/drivers/acpi/osl.c newtree.2/drivers/acpi/osl.c --- newtree/drivers/acpi/osl.c 2006-07-15 14:53:08.000000000 -0700 +++ newtree.2/drivers/acpi/osl.c 2006-08-04 10:39:03.000000000 -0700 @@ -69,6 +69,10 @@ int acpi_specific_hotkey_enabled = TRUE; EXPORT_SYMBOL(acpi_specific_hotkey_enabled); +#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD +int acpi_must_unregister_table = FALSE; +#endif + static unsigned int acpi_irq_irq; static acpi_osd_handler acpi_irq_handler; static void *acpi_irq_context; @@ -219,6 +223,67 @@ return AE_OK; } +#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD +struct acpi_table_header * acpi_find_dsdt_initrd(void) +{ + struct file *firmware_file; + mm_segment_t oldfs; + unsigned long len, len2; + struct acpi_table_header *dsdt_buffer, *ret = NULL; + struct kstat stat; + /* maybe this could be an argument on the cmd line, but let's keep it simple for now */ + char *ramfs_dsdt_name = "/DSDT.aml"; + + printk(KERN_INFO PREFIX "Looking for DSDT in initramfs... "); + + /* + * Never do this at home, only the user-space is allowed to open a file. + * The clean way would be to use the firmware loader. But this code must be run + * before there is any userspace available. So we need a static/init firmware + * infrastructure, which doesn't exist yet... + */ + if (vfs_stat(ramfs_dsdt_name, &stat) < 0) { + printk("error, file %s not found.\n", ramfs_dsdt_name); + return ret; + } + + len = stat.size; + /* check especially against empty files */ + if (len <= 4) { + printk("error file is too small, only %lu bytes.\n", len); + return ret; + } + + firmware_file = filp_open(ramfs_dsdt_name, O_RDONLY, 0); + if (IS_ERR(firmware_file)) { + printk("error, could not open file %s.\n", ramfs_dsdt_name); + return ret; + } + + dsdt_buffer = ACPI_ALLOCATE(len); + if (!dsdt_buffer) { + printk("error when allocating %lu bytes of memory.\n", len); + goto err; + } + + oldfs = get_fs(); + set_fs(KERNEL_DS); + len2 = vfs_read(firmware_file, (char __user *)dsdt_buffer, len, &firmware_file->f_pos); + set_fs(oldfs); + if (len2 < len) { + printk("error trying to read %lu bytes from %s.\n", len, ramfs_dsdt_name); + ACPI_FREE(dsdt_buffer); + goto err; + } + + printk("successfully read %lu bytes from %s.\n", len, ramfs_dsdt_name); + ret = dsdt_buffer; +err: + filp_close(firmware_file, NULL); + return ret; +} +#endif + acpi_status acpi_os_table_override(struct acpi_table_header * existing_table, struct acpi_table_header ** new_table) @@ -226,13 +291,20 @@ if (!existing_table || !new_table) return AE_BAD_PARAMETER; + *new_table = NULL; + #ifdef CONFIG_ACPI_CUSTOM_DSDT if (strncmp(existing_table->signature, "DSDT", 4) == 0) *new_table = (struct acpi_table_header *)AmlCode; - else - *new_table = NULL; -#else - *new_table = NULL; +#endif +#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD + if (strncmp(existing_table->signature, "DSDT", 4) == 0) { + struct acpi_table_header* initrd_table = acpi_find_dsdt_initrd(); + if (initrd_table) { + *new_table = initrd_table; + acpi_must_unregister_table = TRUE; + } + } #endif return AE_OK; } diff -urN newtree/drivers/acpi/tables/tbget.c newtree.2/drivers/acpi/tables/tbget.c --- newtree/drivers/acpi/tables/tbget.c 2006-07-15 14:53:08.000000000 -0700 +++ newtree.2/drivers/acpi/tables/tbget.c 2006-08-04 10:39:03.000000000 -0700 @@ -278,6 +278,14 @@ address.pointer.logical = new_table; status = acpi_tb_get_this_table(&address, new_table, table_info); + +#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD + if (acpi_must_unregister_table) { + ACPI_FREE(new_table); + acpi_must_unregister_table = FALSE; + } +#endif + if (ACPI_FAILURE(status)) { ACPI_EXCEPTION((AE_INFO, status, "Could not copy ACPI table")); return_ACPI_STATUS(status); diff -urN newtree/include/acpi/acpiosxf.h newtree.2/include/acpi/acpiosxf.h --- newtree/include/acpi/acpiosxf.h 2006-07-15 14:53:08.000000000 -0700 +++ newtree.2/include/acpi/acpiosxf.h 2006-08-04 10:39:03.000000000 -0700 @@ -95,6 +95,10 @@ acpi_os_table_override(struct acpi_table_header *existing_table, struct acpi_table_header **new_table); +#ifdef CONFIG_ACPI_CUSTOM_DSDT_INITRD +extern int acpi_must_unregister_table; +#endif + /* * Spinlock primitives */ diff -urN newtree/init/main.c newtree.2/init/main.c --- newtree/init/main.c 2006-08-02 07:14:23.000000000 -0700 +++ newtree.2/init/main.c 2006-08-04 10:39:03.000000000 -0700 @@ -601,8 +601,6 @@ check_bugs(); - acpi_early_init(); /* before LAPIC and SMP init */ - /* Do the rest non-__init'ed, we're now alive */ rest_init(); } @@ -719,6 +717,14 @@ */ child_reaper = current; + /* + * Do this before initcalls, because some drivers want to access + * firmware files. + */ + populate_rootfs(); + + acpi_early_init(); /* before LAPIC and SMP init */ + smp_prepare_cpus(max_cpus); do_pre_smp_initcalls(); @@ -728,12 +734,6 @@ cpuset_init_smp(); - /* - * Do this before initcalls, because some drivers want to access - * firmware files. - */ - populate_rootfs(); - do_basic_setup(); /*